1. Field of the Invention
The present invention relates to a liquid crystal display apparatus. More particularly, it relates to a mounting structure of an optical member such as a reflection sheet, a diffusion sheet, or a diffusion plate.
2. Description of Related Art
A liquid crystal display apparatus is of a thin type, is lightweight, and is low in power consumption, and is widely used for a notebook PC, a monitor for PC, a household TV set, or the like. The liquid crystal display apparatus transmits a light emitted from a backlight through a liquid crystal cell to form a picture. The liquid crystal display apparatus includes optical members such as a reflection sheet for reflecting a light emitted from the backlight, a diffusion plate for diffusing a light emitted from the backlight and a light reflected by the reflection sheet, and a diffusion sheet disposed in stacked relation with the diffusion plate, and for enhancing the diffusion effect of light.
In the liquid crystal display apparatus, the reflection sheet is attached to a rear frame by an adhesion sheet. After attaching the reflection sheet to the rear panel, a backlight is mounted. To the rear frame, the reflection sheet and the backlight are disposed, and a light frame for fixing the backlight is disposed. The diffusion plate and the diffusion sheet are mounted in the following configuration. The diffusion sheet is stacked on the diffusion plate, and the lamination is mounted on the light frame. In such a state, the lamination is pressed by a guide member from the top.
The display performance of the liquid crystal display apparatus largely changes according to the precision of position of the diffusion plate and the diffusion sheet with respect to the rear frame and the backlight. However, in a conventional liquid display apparatus, the reflection sheet, the diffusion plate, and the diffusion sheet are aligned for mounting. Thus, problems may occur in terms of structure or (and) performance due to variations in operation.
Under such circumstances, the invention described in JP-A-2005-91821 discloses the following liquid crystal display apparatus. Namely, the liquid crystal display apparatus includes a reflection sheet, a light source, a light guide plate, and optical sheets (diffusion sheet, prism sheet, and protective sheet) disposed between a main frame and a sub frame. The small projections formed on the main frame and the sub frame penetrate through the openings formed in the optical sheets, so that the optical sheets are aligned.
Whereas, the invention described in JP-A-2004-258236 discloses the following liquid crystal display apparatus. Namely, the liquid crystal display apparatus has a wall portion rising vertically from the outer peripheral portion of the rectangular bottom surface. It is configured such that the projections of a light guide plate and the projections of a liquid crystal display panel are inserted into the holes formed in the wall portion.
However, with the invention described in JP-A-2005-91821, the small projections are penetrated through the holes formed in a plurality of optical sheets. Therefore, holes must be opened in all the optical sheets, which takes time and effort. Further, the holes must be formed so as to be aligned precisely when a plurality of the optical sheets have been stacked one on another. This requires processing precision.
Still further, with the invention described in JP-A-2004-258236, the projections must be formed in the light guide plate and the liquid crystal display panel. Thus, manufacturing of the light guide plate and the liquid crystal display panel takes time and effort. Whereas, provision of the projections results in the complicated shape, which complicates the manner in which a force is exerted thereon. As a result, a stress may concentrate on an unexpected site, leading to breakage.